1. Field of Invention
This invention is related to a brake device which contains a failure detection device.
2. Description of Related Art
An example of a brake device which contains a failure detection device is mentioned in Japanese Laid-Open Patent Application No. 11-278238. In this Japanese Application, a brake device comprises {circle around (1)} a brake operation position detection device which detects the position of a brake pedal, {circle around (2)} a brake fluid pressure detection device which detects the pressure of the brake fluid, {circle around (3)} failure detection device which detects fluid leakage based on the relations between the detected brake fluid pressure by the brake fluid pressure detection device and the detected brake operation position by the brake operation position detection device, and {circle around (4)} a brake fluid pressure control device which controls the brake fluid pressure in different patterns based on whether fluid leakage is detected or not by the failure detection device.
The brake fluid pressure control device comprises an electromagnetic fluid pressure control valve which can control the brake fluid pressure, and the supply of electric current to the electromagnetic fluid control valve is controlled so that the brake pressure depends on the amount of brake operation. The output gain to decide this amount of supply electric current is enlarged more compared to the case where the fluid leakage is not detected. Therefore, the decline of a brake fluid pressure caused by the fluid leakage can be controlled.
However, in the above mentioned brake device, only fluid leakage failure was detected, and the several types of failures are not detected distinctively. Therefore, for example, the type of failure might not be distinguished, and the control of the brake pressure might not be done appropriately at the time of the failure.
The subject of this invention is that the types of the failures can be detected and distinguished, and the brake fluid pressure can therefore be controlled appropriately at the time when the failure is detected.
A brake device having a fluid pressure source device which generates the fluid pressure based on the operation of a brake operating member, and that is actuated by the fluid pressure generated by the fluid pressure source, comprises: a brake operating amount detector which detects the operating amount of the brake operating member, a fluid source pressure detector which detects the pressure generated in the fluid pressure source device, and a failure detector which detects the types of the failures distinctively of the brake device based on the pressure detected by the fluid source pressure detector and the amount of the brake operation detected by the brake operating amount detector.
In this brake device, the types of the failures in the brake device are detected distinctively based on the amount of brake operation and the pressure of the fluid pressure source device. For example, since the conditions of the fluid pressure source device are different based on the types of the failures, the types of the failures are detected distinctively based on the pressure of the fluid pressure source device corresponding to the amount of the brake operation.